80S-2080F480F4-680F5 User’s Manual.pdf - 第631页

11 Station Extensions/Options SIPLACE 80S-20/F4/F4-6/F5 User’s M anual 11.6 Ceramic Substrate Centering Edition 03/98 fr om Software Version SR.404.xx 11 - 34 l Structure of the fiducial Proposal 1 Struct ure of the fidu…

SIPLACE 80S-20/F4/F4-6/F5 User’s Manual 11 Station Extensions/Options

Edition 03/98 from Software Version SR.404.xx 11.6 Ceramic Substrate Centering

11 - 33

This oblique lighting unit can be switched on as an alternative to the existing lighting (see the table in Section

11.6.2).

NOTE

The oblique lighting unit can only be used with the undergantry camera.

11.6.5.2 Fiducial Recommendations for Ceramic Substrates

With ceramic substrates the contrast between the carrier material and the conductor layer is generally very

low. For this reason when fiducials are selected, certain criteria must be observed regarding the shape and

structure of the fiducials. Our recommendations regarding the shape and structure of the fiducials are given

below.

l Shape of the fiducial

We suggest a rectangle or square with a side length of >

1 mm and a free space around it of not less than

0.5 mm.

Fig. 11.6.4 Recommended shape for a fiducial

NOTE

Simple crosses are also suitable, but do require more space.

0.5 mm

1.0 mm

11 Station Extensions/Options SIPLACE 80S-20/F4/F4-6/F5 User’s Manual

11.6 Ceramic Substrate Centering Edition 03/98 from Software Version SR.404.xx

11 - 34

l Structure of the fiducial

Proposal 1

Structure of the

fiducial

Black resistor paste as background. Conductor paste printed onto this as fiducial.

Recommendation Background 0.75 mm larger than the fiducial on all sides.

Type of lighting Normal light

Advantage Good contrast; good definition

Reference Conductor layer

Assessment This combination gives the best results. Highly recommended.

Proposal 2

Structure of the

fiducial

Fiducial made of conductor track material; for example, 6119 and with passivation

glass 4330 overprinted.

Type of lighting Oblique light

Advantage No additional operational step necessary

Reference Conductor layer

Assessment Fiducials are not so well defined as with Proposal 1. Recommended.

Proposal 3

Structure of the

fiducial

Fiducials made of the conductor track layer against a background of exposed ceramic

Type of lighting Oblique light or normal light (depending on the paste)

Advantage No additional operational step necessary

Reference Conductor layer

Comment Fiducials are not so well defined as with Proposal 2.

Fiducial imaging depends on the surrounding free area. Each circuit may need to be

taught separately.

Assessment Recommended with qualifications.

SIPLACE 80S-20/F4/F4-6/F5 User’s Manual 11 Station Extensions/Options

Edition 03/98 from Software Version SR.404.xx 11.7 Dispenser Flux Application Unit for SIPLACE 80F4/F4-6/F5

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11.7 Dispenser Flux Application Unit for SIPLACE 80F

-6/F

11.7.1 General Comments

If flip-chip components are to be processed properly and reliably, a flux must be applied before the compo-

nent is inserted. This ensures that the soldering process which follows runs smoothly and dependably.

Once the flip-chip component has been picked up by the IC head and positional measurement carried out,

flux is applied to the placement position on the board. The quantity of flux which is to be applied can be spec-

ified for each package form.

Immediately following application of the flux the IC head inserts the flip chip. The IC head holds the flip-chip

component firmly in place on the board for a period of time which can be programmed and which is specific to

the package form. This causes the component to dry onto the flux and thus not be able to ‚float away‘.

Once all flip-chip components have been inserted, a programmable period of waiting follows, after which the

board conveyor is activated and the board transported onwards.

11.7.2 Function

The centrifuge tube is filled with flux and functions as a reservoir. The flux is sucked into the syringe via the

valve by means of a pump. The syringe now dispenses the preset amount of flux onto the placement position

via the valve and the tip of the dispensing needle.